1,721,023 research outputs found
Ostalactones A-C, β- and ε-lactones with lipase inhibitory activity from the cultured basidiomycete Stereum ostrea
No full textOstalactones A-C (1-3), three new β- and ε-lactone natural products, were isolated from the culture broth of the basidiomycete Stereum ostrea. The structures were elucidated by interpretation of HRFABMS and 1D and 2D NMR data. The structures of 1 and 2 are characterized by the presence of a β-lactone containing a fused 4/5 bicyclic core structure. Compound 3 possesses a 2-oxepinone ring system, which is likely to be a biosynthetic precursor of compounds 1 and 2. Ostalactones A (1) and B (2) displayed potent inhibitory activity against human pancreatic lipase.open
New Chromene Derivatives with Radical Scavenging Activities from the Brown Alga Sargassum Siliquastrum
No full text The organic extract of Sargassum siliquastrum exhibited in vitro radical scavenging activity in our screening of marine brown algae collected in Jeju Island, Korea. Bioactivity-guided fractionation of the organic extract led to the isolation of two new meroterpenoids, named sargachromanols S and T, along with the known meroterpenoids, isopolycerasoidol, nahocol D2, and sargachromanols D, E, G, and I. The planar structures of the new compounds were determined by the analysis of spectroscopic data obtained by HREIMS and 1D and 2D NMR. The structures of the new compounds sargachromanols S and T were closely related to those of previously isolated sargachromanols D and A, respectively. The isolated compounds showed radical scavenging activities in vitro against 1,1-diphenylpicrylhydrazyl and 2,2'-azidobis(3-ethylbenzothiazoline-6-sulfonate) radicals. </jats:p
Inoscavin A, a new free radical scavenger from the mushroom Inonotus xeranticus
No full textA new free radical scavenger named inoscavin A was isolated from the methanolic extract of the mushroom Inonotus xeranticus. The structure of inoscavin A was elucidated by NMR spectroscopic method.open
Benzastatins A, B, C and D : new free radical scavengers from Streptomyces nitrosporeus 30643 : II. structure determination
No full textThe structures of benzastatins A, B, C, and D, new free radical scavengers, were determined by spectroscopic studies. Benzastatins A and B incorporate the para-aminobenzamide unit which is rare in fungal metabolites. Benzastatins C and D are unique alkaloids related to virantmycin; they contain the tetrahydroquinoline unit in the molecules.open
Leucomentin-5 and -6, two new Leucomentin derivatives from the mushroom Paxillus panuoides
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Curtisians A-D, new free radical scavengers from the mushroom Paxillus curtisii
No full textIn our continuous investigation for free radical scavengers from extracts of fruit body of basidiomycetes, we have isolated four new p-terphenyl compounds, designated as curtisians A~D, from the methanolic extract of the fruit body of Paxillus curtisii. These compounds were isolated by silica gel and Sephadex LH-20 column chromatographies, preparative-TLC and HPLC, consecutively. The structures of curtisians were assigned as p-terphanyls with substituents of acetyl, benzoyl, phenylbutyryl, 3-hydroxybutyryl and 3-acetoxybutyryl. Curtisians A, B, C and D exhibited inhibitory activity against lipid peroxidation with IC50 values of 0.15, 0.17, 0.24 and 0.14 μg/ml, respectively.open
Antiphotooxidative activity of protoberberines derived from coptis japonica makino in the chlorophyll-sensitized photooxidation of oil
No full textAntiphotooxidative components were isolated from the methanolic extract of Coptis japonica Makino by liquid-liquid partitioning fractionation, subsequent column chromatography on Sephadex LH20 and silica gel, and preparative silica gel TLC. The isolated compounds were identified as coptisine, jatrorrizhine, berberine, and magnoflorine by a combination of spectroscopic studies using UV-visible, IR, mass-spectrometry, and NMR. Coptisine, jatrorrizhine, and berberine isolated from Coptis japonica Makino showed strong antiphotooxidative activity in the chlorophyll-sensitized photooxidation of linoleic acid. However, these compounds did not show either inhibitory activity against lipid peroxidation in rat liver microsomes nor DPPH radical scavenging activity, indicating that their antiphotooxidative activity was not due to the radical chain reaction breaking ability but due to singlet oxygen quenching activity. Commercially available authentic protoberberines (berberine chloride and palmatine chloride) also showed strong antioxidative activity in the chlorophyllsensitized photooxidation of linoleic acid. The antiphotooxidative activities of the berberine chloride and palmatine chloride were significantly higher than that of ascorbyl palmitate in the chlorophyllsensitized photooxidation of linoleic acid. These results clearly showed for the first time the antiphotooxidative properties of protoberberines in chlorophyll-sensitized photooxidation of oil.open
Lepistatins A–C, chlorinated sesquiterpenes from the cultured basidiomycete Lepista sordida
No full textThree new chlorinated sesquiterpenes, named lepistatins A？C, were isolated from the culture broth of Basidiomycete Lepista sordida. The structures were determined by the analysis of spectroscopic data including HREIMS and 1D and 2D NMR. The absolute configuration of lepistatin B was determined by comparing the specific rotation and circular dichroism spectrum with those of known structurally related compounds bearing the same chiral carbon. The structures of lepistatins A？C feature the indanone core structure, but differ from other indanone-containing sesquiterpenes of fungal origin by the alkyl substitution pattern. This indicates that lepistatins A？C probably possess a new sesquiterpene scaffold derived from the common precursor, trans-humulyl cation, by an alternative cyclization.
Two p-terphenyls from mushroom Paxillus panuoides with free radical scavenging activity
No full textAs part of a continuing investigation to identify free radical scavengers from the fruit bodies of basidiomycetes, we isolated two p- terphenyl compounds, designated as PA1 and PA21, from methanolic extract of the fruit body of Paxillus panuoides. The methanolic extract was processed by ethyl acetate extraction and silica gel column chromatography to yield two active fractions. PA1 was obtained from one of the fractions through Sephadex LH-20 and silica gel column chromatographies and reverse-phase HPLC. The other fraction was purified by Sephadex LH-20 and reverse-phase column chromatographies to produce PA2. The compounds PA1 and PA2 were identified as leucomentin-4 and leucomentin-2, respectively, on the basis of various spectroscopic analyses. These compounds exhibited strong inhibitory activities against lipid peroxidation in rat liver microsomes with IC50 values of 0.10 and 0.06 μg/ml, respectively.open
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